Africa
Africa is the world's second-largest and second-most-populous continent. There are 54 contries. At about 30.2 million km2 (11.7 million including adjacent islands, it covers six percent of the Earth's total surface area and 20.4 percent of the total land area.
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It can also be considered a northern subcontinent of the Americas.[1] It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea. There is 23 contries in north America.
South America
South America is a continent located in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. It can also be considered as a subcontinent of the Americas.
South America has an area of 17,840,000 square kilometers (6,890,000 sq mi). Its population as of 2005 has been estimated at more than 371,090,000. South America ranks fourth in area (after Asia, Africa, and North America) and fifth in population (after Asia, Africa, Europe, and North America).